Following on from the recent post GCP Templates for C4 Diagrams using PlantUML, cloud architects are often challenged with producing diagrams for architectures spanning multiple cloud providers, particularly as you elevate to enterprise level diagrams.
In this post, with the magic of !includeurl we have brought PlantUML template libraries together for AWS, Azure and GCP icon sets, allowing us to produce multi cloud C4 diagrams using PlantUML like this one:
Multi Cloud Architecture Diagram using PlantUML
Creating a multi cloud diagram is simple, start by adding the following include statements after the @startuml label in a new PlantUML C4 diagram:
Then add references to the required services from different providers…
Then include the predefined resources from your different cloud providers in your diagram as shown here (describing a client server application over a cloud to cloud VPN between Azure and GCP)…
This article demonstrates creating a site to site IPSEC VPN connection between a GCP VPC network and an Azure Virtual Network, enabling private RFC1918 network connectivity between virtual networks in both clouds. This is done using a single PowerShell script leveraging Azure PowerShell and gcloud commands in the Google SDK.
Additionally, we will use Azure Private DNS to enable private access between Azure hosts and GCP APIs (such as Cloud Storage or Big Query).
An overview of the solution is provided here:
Azure to GCP VPN Design
One note before starting – site to site VPN connections between GCP and Azure currently do not support dynamic routing using BGP, however creating some simple routes on either end of the connection will be enough to get going.
Let’s go through this step by step:
Step 1 : Authenticate to Azure
Azure’s account equivalent is a subscription, the following command from Azure Powershell is used to authenticate a user to one or more subscriptions.
Connect-AzAccount
This command will open a browser window prompting you for Microsoft credentials, once authenticated you will be returned to the command line.
Step 2 : Create a Resource Group (Azure)
A resource group is roughly equivalent to a project in GCP. You will need to supply a Location (equivalent to a GCP region):
Step 3 : Create a Virtual Network with Subnets and Routes (Azure)
An Azure Virtual Network is the equivalent of a VPC network in GCP (or AWS), you must define subnets before creating a Virtual Network. In this example we will create two subnets, one Gateway subnet (which needs to be named accordingly) where the VPN gateway will reside, and one subnet named ‘default’ where we will host VMs which will connect to GCP services over the private VPN connection.
Before defining the default subnet we must create and attach a Route Table (equivalent of a Route in GCP), this particular route will be used to route ‘private’ requests to services in GCP (such as Big Query).
Network Security Groups in Azure are stateful firewalls much like Firewall Rules in VPC networks in GCP. Like GCP, the lower priority overrides higher priority rules.
In the example we will create several rules to allow inbound ICMP, TCP and UDP traffic from our Google VPC and RDP traffic from the Internet (which we will use to logon to a VM in Azure to test private connectivity between the two clouds):
We need to create two Public IP Address (equivalent of an External IP in GCP) which will be used for our VPN gateway and for the VM we will create:
# create public IP address for VM
$vmpip = New-AzPublicIpAddress `
-Name "vm-ip" `
-ResourceGroupName "azure-to-gcp" `
-Location "Australia Southeast" `
-AllocationMethod Dynamic
# create public IP address for NW gateway
$ngwpip = New-AzPublicIpAddress `
-Name "ngw-ip" `
-ResourceGroupName "azure-to-gcp" `
-Location "Australia Southeast" `
-AllocationMethod Dynamic
Step 6 : Create Virtual Network Gateway (Azure)
The Virtual Network Gateway in Azure is the VPN Gateway equivalent in Azure which will be used to create a VPN tunnel between Azure and a GCP VPN Gateway. This gateway will be placed in the Gateway subnet created previously and one of the Public IP addresses created in the previous step will be assigned to this gateway.
# create virtual network gateway
$ngwipconfig = New-AzVirtualNetworkGatewayIpConfig `
-Name "ngw-ipconfig" `
-SubnetId $gatewaySubnet.Id `
-PublicIpAddressId $ngwpip.Id
# use the AsJob switch as this is a long running process
$job = New-AzVirtualNetworkGateway -Name "vnet-gateway" `
-ResourceGroupName "azure-to-gcp" `
-Location "Australia Southeast" `
-IpConfigurations $ngwipconfig `
-GatewayType "Vpn" `
-VpnType "RouteBased" `
-GatewaySku "VpnGw1" `
-VpnGatewayGeneration "Generation1" `
-AsJob
$vnetgw = Get-AzVirtualNetworkGateway `
-Name "vnet-gateway" `
-ResourceGroupName "azure-to-gcp"
Step 7 : Create a VPC Network and Subnetwork(s) (GCP)
A VPC network and subnet need to be created in GCP, the subnet defines the VPC address space. This address space must not overlap with the Azure Virtual Network CIDR. For all GCP steps it is assumed that the project is set for client config (e.g. gcloud config set project <>) so it does not need to be specified for each operation. Private Google access should be enabled on all subnets created.
VPC firewall rules will need to be created in GCP to allow VPN traffic as well as SSH traffic from the internet (which allows you to SSH into VM instances using Cloud Shell).
Now we will create the GCP side of our VPN tunnel using the Public IP Address of the Azure Virtual Network Gateway created in a previous step. As this example uses a route based VPN the traffic selector values need to be set at 0.0.0.0/0. A PSK (Pre Shared Key) needs to be supplied which will be the same key used when we configure a VPN Connection on the Azure side of the tunnel.
As we are using static routing (as opposed to dynamic routing) we will need to define all of the specific routes on the GCP side. We will need to setup routes for both outgoing traffic to the Azure network as well as incoming traffic for the restricted Google API range (199.36.153.4/30).
Now we can setup the Azure side of the VPN Connection which is accomplished by associating the Azure Virtual Network Gateway with the Local Network Gateway. A PSK (Pre Shared Key) needs to be supplied which is the same key used for the GCP VPN Tunnel in step 10.
At this stage we have created an end to end connection between the virtual networks in both clouds. You should see this reflected in the respective consoles in each provider.
GCP VPN Tunnel to a Azure Virtual NetworkAzure VPN Connection to a GCP VPC Network
Congratulations! You have just setup a multi cloud environment using private networking. Now let’s setup Google Private Access for Azure hosts and create VMs on each side to test our setup.
Step 14 : Create a Private DNS Zone for googleapis.com (Azure)
We will now need to create a Private DNS zone in Azure for the googleapis.com domain which will host records to redirect Google API requests to the Restricted API range.
Now we are ready to test connectivity from both sides of the tunnel.
Azure to GCP
Establish a remote desktop (RDP) connection to the Azure VM created in Step 15. Ping the GCP VM instance using its private IP address.
Test Private IP Connectivity from Azure to GCP
GCP to Azure
Now SSH into the GCP Linux VM instance and ping the Azure host using its private IP address.
Test Private IP Connectivity from GCP to Azure
Test Private Google Access from Azure
Now that we have established bi-directional connectivity between the two clouds, we can test private access to Google APIs from our Azure host. Follow the steps below to test private access:
Perform an nslookup to ensure that calls to googleapis.com resolve to the restricted API range (e.g. nslookup storage.googleapis.com). You should see a response showing the A records from the googleapis.com Private DNS Zone created in step 14.
Now test connectivity to Google APIs, for example to test access to Google Cloud Storage using gsutil, or test access to Big Query using the bq command
A few years back, before the rise of the hyper-scalers, I had my first infracode ‘aha moment’ with OpenStack. The second came with Kitchen.
I had already been using test driven development for application code and configuration automation for infrastructure but Kitchen brought the two together. Kitchen made it possible to write tests, spin up infrastructure, and then tear everything down again – the Red/Green/Refactor cycle for infrastructure. What made this even better was that it wasn’t a facsimile of a target environment, it was the same – same VM’s, same OS, same network.
Coming from a Chef background for configuration automation, Kitchen is a great fit to the Ruby ecosystem. Kitchen works with Ansible and Azure, but a Ruby environment and at least a smattering of Ruby coding skills are required.
Molecule provides a similar red-green development cycle to Kitchen, but without the need to step outside of the familiar Python environment.
Out of the box, Molecule supports development of Ansible roles using either a Docker or Virtual Box infrastructure provider. Molecule also leverages the Ansible drivers for private and public cloud platforms.
Molecule can be configured to test an individual role or collections of roles in Ansible playbooks.
This tutorial demonstrates how to use Molecule with Azure to develop and test an individual Ansible role following the red/green/refactor infracode workflow, which can be generalised as:
Red– write a failing infrastructure test
Green – write the Ansible tasks needed to pass the test
Refactor – repeat the process
The steps required for this tutorial are as follows:
Azure setup
Ensure there is an existing Azure Resource Group that will be used for infracode development and testing. Within the resource group, ensure there is a single virtual network (vnet) with a single subnet. Ansible will use these for the default network setup.
Setup a working environment
There are a number of options for setting up a Python environment for Ansible and Molecule, including Python virtualenv or a Docker container environment.
Create a Docker image for Ansible+Molecule+Azure
This tutorial uses a Docker container environment. A Dockerfile for the image can be found in ./molecule-azure-image/Dockerfile. The image sets up a sane Python3 environment with Ansible, Ansible[azure], and Molecule pip modules installed.
Create a Docker workspace
Setup a working environment using the Docker image with Ansible, Molecule, and the azure-cli installed.
This example assumes the following:
a resource group already exists with access rights to create virtual machines; and
the resource group contains a single vnet with a single subnet
Log into an Azure subcription
Ansible supports a number of different methods for authenticating with Azure. This example uses the azure-cli to login interactively.
Create an empty Ansible role with Molecule
Molecule provides an init function with defaults for various providers. The molecule-azure-role-template creates an empty role with scaffolding for Azure.
Check that the environment is working by running the following code:
The output should look be similar to…
Spin up an Azure VM
Spin up a fresh VM to be used for infra-code development.
Molecule provides a handy option for logging into the new VM:
There is now a fresh Ubuntu 18.04 virtual machine ready for infra-code development. For this example, a basic Nginx server will be installed and verified.
Write a failing test
Testinfra provides a pytest based framework for verifying server and infrastructure configuration. Molecule then manages the execution of those testinfra tests. The Molecule template provides a starting point for crafting tests of your own. For this tutorial, installation of the nginx service is verified. Modify the tests file using vi molecule/default/tests/test_default.py
Execute the failing test
The Ansible task needed to install and enable nginx has not yet been written, so the test should fail:
If the initial sample tests in test_default.py are kept, then 3 tests should fail and 2 tests should pass.
Write a task to install nginx
Add a task to install the nginx service using vi tasks/main.yml:
Apply the role
Apply the role to the instance created using Molecule.
The nginx package should now be installed, both enabled and started, and listening on port 80. Note that the nginx instance will not be accessible from the Internet due to the Azure network security rules. The nginx instance can be confirmed manually by logging into the instance and using curl to make a request to the nginx service.
Execute the passing test
After applying the Ansible task to the instance, the testinfra tests should now pass.
Cleanup
Now that the Ansible role works as defined in the test specification, the development environment can be cleaned up.
Molecule removes the Azure resources created to develop and test the configuration role. Note that deletion may take a few minutes.
Finally, once you are done, exit the container environment. If the container was started with the --rm switch, the container will also be removed, leaving you with a clean workspace and newly minted Ansible role with automated test cases.
